At the risk of being redundant, my 1991 RS seems to be shifting weird. TCC feels like it's locking & unlocking intermittently while cruising in Overdrive at 50+ mph. If I shift to Drive instead, I still notice it. One guy told me he thought it was shifting between OD & D, but the RPMs only seem to jump by a hundred or so before going right back to where they were. So quick you don't hear it in the exhaust noise, just feels like a stutter.

My problem: I can't afford a complete rebuild right now (or anytime soon). I am planning on changing the trans fluid & filter. I see that Advanced Auto sells the TCC solenoid (although they call it a Transmission Control Solenoid and say it controls downshifting, not the TCC - looks like this one: https://www.thirdgen.org/forums/tran...ut-lockup.html )

I see that people have commented that a TPS could be part of the problem as well as the CTS (Coolant Temp Sensor?). Is the CTS the one below the passenger exhaust manifold that controls the fan or is there an other one?

They also sell a B&M Shift Improver (I know - ech B&M). Would this or any other DIY shift kit solve the problem or would it just be masking it?

Any advise on additives? Good, bad, or ugly?

 

1) Your TBI car does NOT have a CTS that I know of, so that can't be an issue since there is not one. If it had one, it would be located at intake just beside thermostat housing, and would have a black wire and yellow wire to it.

2) Even the TCC should change RPM's about 400-500 - so if your only seeing a 100rpm change, I'd say maybe another issue.

3) If you have no knowledge of the tranny fluid/filter ever being changed, and the tranny has more than 100,000 miles on it, I wouldn't change it at all. Should get changed every 60,000 miles - if that doesn't happen, then the particulates in the fluid from wearing discs/plates act as a friction additive - when you change that old tranny fluid out, you lose the particulates, so after fluid change you have the potential for the tranny to slip.

So - I'd look elsewhere for an issue. Maybe bad TPS, maybe just needs tune up (plugs, wires, rotor, cap, air/fuel filters). Try some Seafoam in the tank to clean up any gink in the fuel system.

These trannies will "hunt" for a gear, but usually at lower speeds, like 35 - 45 - they can't always seem to decide between 3rd gear and 4th gear. At 50+, you should easily be in 4th with no tranny hunting, unless you accellerate quickly.

Have you checked and adjusted your TV cable?

 

Thank you for the info.

1) explains why i didn't notice a CTS when I replaced the thermostat.

2) I'm guessing at the RPM change (still trying to tweek in the resistors on my tach rebuild) but since it happens only for a fraction of a second (same as my dad's truck which IS the TCC slipping) I thought that might be a likely place to look. If it does turn out to be the TCC, is there a problem with disconnecting the TCC wire so it doesn't keep engaging and disengaging?

3) I don't know about fluid changes in the past. The car obviously sat for quite some time before I bought it. It looks nice and red and doesn't smell bad. It's possible the PO changed it prior to tearing into the TBI and giving up (me mis-diagnosed the TBI and fuel pump as problem instead of the VATS failing). If the trans is slipping due to the PO changing the fluid, are there friction additives that would help?

 

a shift kit won't fix a slipping tranny

miracle in a bottle won't fix a slipping tranny

 

That's kind of what I thought but figured I would cover all angles when asking.

 

Definately replace the control module it seems to be the problem with almost every 700r4/4l60. As far as additives I only trust the lucas oil but it's not a miracle cure.

 

What do you mean by "control module"? The valve mechanism in the trans or the computer under the dash?

 

solenoid/module they get called different names on the advance auto site.
heres one;
http://shop.advanceautoparts.com/web...AMS_1323448807____
heres the other;
http://shop.advanceautoparts.com/web...18260180-P_x_x

 

a tbi does have a cts. as was said its next to the thermostat housing. just wanna clear that up.

 

If the transmission is shifting ok, and you think it is just the torque converter clutch causing the problem, disconnect the male plug at the drivers side of the transmission and see what happens. If it goes away, then it is the torque converter clutch that is coming on & off. Make the test and see what happens, then I will give you some ideas as to what to do here.

 

Thanks, Pro Built. I hope to have time to tinker with it this weekend and I'll let you know what happens.

 

hey so if the plug is pulled and the car shifts fine does that mean that the tcc control module needs changed?

 

It usually means the ECM and wiring system has an intermittent fault (such as a CTS or TPS reading that's unstable)

On some GM cars with TCC and an ALDL under-dash, one of the ALDL wires can be grounded to lock the TCC. If that works and unplugging at the trans. prevents the problem entirely, then the problem is in the control system as mentioned above.

 

I adjusted the idle speed (twice because chilton's has issues), and that seemed to make the clutch converter act a little better. My tps sensor was just a little over volt specs at closed throttle. Now it doesn't lock up until around 40mph so that seems normal. Thanks

 

Turns out it was my speedometer cable. My car has the VSS behind the gauges and the speedo was jumping real bad giving the VSS jumpy readings.

 

Thanks for the follow-up.
That makes sense.

 

Ive been having tons of issues fixed my main one cracked fuel line in tank replaced and regulator tps idles strong now alil high can rev the h*** out oif it in park but as soon as i put it in drive instant kill or reverse is worse its like it slams in reverse and dies instantly....its a 91 L98 350 in a 92 rs changed the kick down cable and ecm with swap ohh speedo doesnt work guages fine idk if there related also rebuilt tpi and manifold any ideas one please??? really need to get it back on the road and am at a loss on ideas

 

Im not a real expert but it sounds like your torque converter clutch isn't unlocking. I am thinking there is a sensor on the brake pedal that unlocks the tcc when you hit the brake. If your speedo isn't working it might be your vss sensor. I assume that on a 92 its in the transmission. If thats not working it should unlock the tcc. Try unplugging the tcc. Mine is on the driver side of the tranny and is a square four prong adapter. I am still learning how these systems work so I could be wrong. Just shooting you some ideas.